What does B0145 mean on a Chevy?

B0145. Rear auxiliary mode actuator command circuit malfunction. The HVAC module cannot move the rear air door and sets a body warning. Applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.

What causes B0145 on a Chevy?

Failed rear auxiliary mode actuator with a worn motor Rear auxiliary mode door binding in its travel Open or short in the rear auxiliary mode actuator command circuit Corroded or loose rear auxiliary mode actuator connector Faulty output inside the rear auxiliary HVAC control module

How do I fix B0145 on a Chevy?

Confirm the code with a scan tool and command the rear auxiliary mode door through full travel Inspect the rear auxiliary mode actuator connector for corrosion and pin damage Test the command and reference circuits at the rear auxiliary mode actuator with a multimeter Check the rear auxiliary mode door for binding and move it by hand with the actuator removed Replace the rear auxiliary mode actuator only if the circuits test good, then clear the code and retest

Code

B0145

Rear auxiliary mode actuator command circuit malfunction

Category: Body
Severity: Body Warning Light
Applies to: Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code
Related: No single generic twin. See OBD Codes List

What it means

B0145. Rear auxiliary mode actuator command circuit malfunction. The HVAC module cannot move the rear air door and sets a body warning. This Chevy-enhanced code applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.

Findings, check these first

Failed rear auxiliary mode actuator with a worn motor
Rear auxiliary mode door binding in its travel
Open or short in the rear auxiliary mode actuator command circuit
Corroded or loose rear auxiliary mode actuator connector
Faulty output inside the rear auxiliary HVAC control module

Standard procedure

Confirm the code with a scan tool and command the rear auxiliary mode door through full travel
Inspect the rear auxiliary mode actuator connector for corrosion and pin damage
Test the command and reference circuits at the rear auxiliary mode actuator with a multimeter
Check the rear auxiliary mode door for binding and move it by hand with the actuator removed
Replace the rear auxiliary mode actuator only if the circuits test good, then clear the code and retest

Look up another code

Press / to jump to the box. Chevy-enhanced powertrain, body, chassis and network codes.

Sources and review

Review: qualified. Read the source limits below.

Code B0145 definition | OBDII.pro
live manufacturer definition (obdii.pro)
Supports: GM manufacturer meaning for B0145
Fetched directly. The GM entry is the brand-family meaning used here. This site is independent of engine-codes and autocodes.
B0145 CHEVROLET Auxiliary Mode Actuator | Engine-Codes.com
archived reference page (engine-codes.com via Wayback Machine)
Supports: Chevrolet meaning and possible causes
Fetched directly. Model and year fitment remain curator claims.
B0145 CHEVROLET Auxiliary Mode Actuator | AutoCodes.com
archived reference page (autocodes.com via Wayback Machine)
Supports: corroboration of Chevrolet meaning and causes
Same Chevrolet text as the engine-codes page (both sites share one publisher).

Review note: obdii.pro GM names the rear air flow position command circuit; the archive names the auxiliary mode actuator. The archive pair is one publisher

Last updated 2026-10-10.

Report a correction for B0145. Include your vehicle, the issue and a source if you have one.